<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../js/jquery-3.6.0.min.js"></script>
</head>
<body>
    <ul id="nav">
       <li>
        <a href="javascript:;">菜单一</a>
        <ul>
            <li>子1</li>
            <li>子2</li>
            <li>子3</li>
        </ul>
    </li> 
    </ul>
    <script src="../js/shop.js"></script>
</body>
</html>